3. CRUSTAL MOVEMENT OBSERVATION NETWORK OF CHINA
Crustal Movement Observation Network of China (acronym for CMONOC) was based on the global
positioning system (GPS) observations technology, associated with spatial technologies of the radio Very Long
Baseline Interferometry (VLBI) and human-ranging ( SLR), precision gravity and the precision leveling in a
large-scale, high precision and high temporal and spatial resolution of the crustal movement. CMONOC was a
comprehensive, multi-purpose, open, data sharing resources, nationwide observation network, with continuous
dynamic monitoring function. Networks essentially improved the dynamic monitoring matters in the Earth's
surface solid, liquid, gas.
The network was composed of datum network, basis network, regional network and analysis system. Datum
network includes 25 GPS observation stations, with many observation means, such as absolute gravity, relative
gravity and level. Some stations can observe objects using VLBI and SLR, and every station was equipped with
satellite communications and cable communications equipment. 56 regular re-testing GPS stations consist of
the basis network. The frequency in west was two one year, and four times in east. Regional Network owns
1000 regular re-testing GPS stations, of which about 300 distribute equably, and about 700 laid intensively in
the fault zone and earthquakes surveillance zone.
Accuracy of the baseline length changed rate per-year between two datum networks was better than 2 mm. GPS
satellite precise orbit accuracy and the IGS network were better than 0.5 meters, and independent orbit accuracy
was better than two meters. Measure accuracy of datum change rate of VLBI between adjacent stations was 2-3
mm. Absolute coordinates accuracy of fixed SLR was better 3 cm, mobile SLR better than 5 cm. Absolute
gravity accuracy was better than 5-Gaya.The GPS baseline between basis stations and regional stations was also
required, the horizontal component 3-5 mm, vertical component 10-15 mm, and the relative gravity accuracy 15
to 20-Gaya.
The observation crustal movement data was basis of quantitative study of earth science. These data with
large-scale and time continuity were very valuable data resources about quantitative research in China region
even the global plate movement.